1. Field of the Invention
This invention relates generally to the field of fully automated testing systems for integrated circuits and the like, such testing systems being used to conduct quality control tests of electronic structural components. In particular, the invention relates to a positioning device for test heads forming part of such automatic testing systems.
2. Prior Art
During the manufacture of electronic structural components and the like, it is necessary to conduct quality control tests. Such tests are normally conducted by fully automated testing systems which are connected to an integrated circuit sorting system through a test head. The test head is normally connected to the testing system by overhead cables, enabling the test head to be moved into and out of an operative position. Support devices, which are sometimes referred to as test head manipulators, are used to position such test heads over wafer/samplers, and to move such test heads into ergonomically favorable positions to facilitate manual testing of electronic components, as well as adjustments and/or repairs made directly on the test head. Such test heads and the necessary connecting cables can weigh as much as 1,000 newtons, approximately 225 pounds.
In order for the test heads to be properly positioned, it is necessary that a test head manipulator enable or otherwise provide not only height adjustment, but movements in two coordinate directions of a horizontal plane, a rotation in the horizontal plane and a tilting motion around a horizontal axis, as well.
In one such test head manipulator known in the art, the moveable portion of the test head is carried by a vertical member supported by fork-like extending legs. A worm/gear spindle assembly provides for height adjustment and two parallel cylinders enable translation in a horizontal plane. The two cylinders are arranged symmetrically relative to the support, a hinged fitting for the test head being mounted therebetween and manually adjustable. There is no provision for sideways movement, although the test head can be rotated about the vertical axis of the support column and can be tilted around a horizontal axis. Test heads of differing width can be accommodated only by changing the brackets which provide for the horizontal motion. Such construction limits accessibility to the back of the test heads.
Another known manipulator comprises a vertical column or standard of C-shaped cross section, being open on one side. The test head carrier is clamped on a cylinder, the cylinder being mounted on the column. The test head carrier is shaped as a rigid bracket and is adjustable by a three-way flexibly arranged carrier bracket construction in the horizontal plane. Test heads of differing width can be accommodated only by an exchange of the rigid bracket or by the insertion of adaptors between the bracket and test head. Accessibility to the back of the test head is also limited, due to the bracket design and the compact construction of the carrier bracket.